Vulnerability · Published Oct 28, 2026 · Assigned by GitHub_M
CVE-2026-118243Highcharts Dashboards: `__proto__` data table id writes sync listeners to `Object.prototype`
Medium 5.3
In plain English
A medium-severity prototype pollution in highcharts from highcharts. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 29% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Highcharts JS is a JavaScript charting library based on SVG. From 1.0.0 until 4.2.2, Highcharts Dashboards stores DataCursor listener and state maps in plain objects keyed by DataTable ID. A __proto__ table ID supplied through dataPool connector configuration resolves to Object.prototype, and sync registration creates an enumerable property there whose suffix can be influenced through the sync group option. The property is visible on every object, and lasting sync states can throw and stop features such as extremes synchronization. Exploitation requires untrusted dashboard configuration and an enabled component sync, but no user interaction beyond loading the board. This issue is fixed in 4.2.2.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @highcharts/dashboards | 4.2.2 | GHSA-jqgh-w3cc-7jqw |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| highcharts | highcharts | >= 1.0.0, < 4.2.2 |
Weakness: CWE-1321 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:L/SI:L/SA:L